PureBasic

Check if a Remote File or Directory Exists

Demonstrates the Chilkat SFtp.FileExists method, which checks a remote path and returns an integer describing what is there. The first argument is the remote path and the second (followLinks) selects whether a symbolic link is followed to its target. The return value is -1 on error, 0 if nothing exists, 1 for a file, 2 for a directory, 3 for a symbolic link, and higher values for special entry types.

Background: This returns more than a yes/no because "does it exist" usually comes with "and is it the kind of thing I expect" — a job that means to write a file should notice if a directory already occupies the path. The followLinks flag decides whether a symbolic link is reported as a link (3, only when not following) or transparently resolved to its target's type. Always handle the -1 case: it means the check itself failed, which is different from the path not existing.

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IncludeFile "CkSFtp.pb"

Procedure ChilkatExample()

    success.i = 0

    ;  Demonstrates the SFtp.FileExists method, which checks a remote path and returns an integer
    ;  describing what is there.  The 1st argument is the remote path and the 2nd (followLinks)
    ;  selects whether a symbolic link is followed to its target.

    sftp.i = CkSFtp::ckCreate()
    If sftp.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ;  Connect, authenticate, and initialize the SFTP subsystem.
    port.i = 22
    success = CkSFtp::ckConnect(sftp,"sftp.example.com",port)
    If success = 0
        Debug CkSFtp::ckLastErrorText(sftp)
        CkSFtp::ckDispose(sftp)
        ProcedureReturn
    EndIf

    ;  Normally you would not hard-code the password in source.  You should instead obtain it
    ;  from an interactive prompt, environment variable, or a secrets vault.
    password.s = "mySshPassword"

    success = CkSFtp::ckAuthenticatePw(sftp,"mySshLogin",password)
    If success = 0
        Debug CkSFtp::ckLastErrorText(sftp)
        CkSFtp::ckDispose(sftp)
        ProcedureReturn
    EndIf

    success = CkSFtp::ckInitializeSftp(sftp)
    If success = 0
        Debug CkSFtp::ckLastErrorText(sftp)
        CkSFtp::ckDispose(sftp)
        ProcedureReturn
    EndIf

    ;  When followLinks is 1, a symbolic link is followed and the target's type is returned.
    followLinks.i = 1
    result.i = CkSFtp::ckFileExists(sftp,"subdir/report.pdf",followLinks)

    ;  Interpret the return value.
    If result = -1
        Debug CkSFtp::ckLastErrorText(sftp)
        CkSFtp::ckDispose(sftp)
        ProcedureReturn
    EndIf

    If result = 0
        Debug "The path does not exist."
    EndIf

    If result = 1
        Debug "A regular file exists."
    EndIf

    If result = 2
        Debug "A directory exists."
    EndIf

    ;  Other possible values: 3 = symbolic link (only when followLinks is 0), 4 = special
    ;  entry, 5 = unknown, 6 = socket, 7 = character device, 8 = block device, 9 = FIFO.

    CkSFtp::ckDisconnect(sftp)


    CkSFtp::ckDispose(sftp)


    ProcedureReturn
EndProcedure